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Members of this phylum are physiologically diverse, and can be found in a variety of environments including soil, hot springs, oceans, caves, and metal-contaminated soils.[5] The members of this phylum are particularly abundant in soil habitats representing up to 52% of the total bacterial community.[6] Environmental factors such as pH and nutrients have been seen to drive Acidobacteria dynamics.[7][8][9] Many Acidobacteria are acidophilic, including the first described member of the phylum, Acidobacterium capsulatum.[10]

As well as their natural soil habitat, unclassified subdivision 2 Acidobacteria have also been identified as a contaminant of DNA extraction kit reagents, which may lead to their erroneous appearance in microbiota or metagenomic datasets.[17]

Members of subdivision 1 have been found to dominate in low pH conditions.[18][7] Additionally, Acidobacteria from acid mine drainage have been found to be more adapted to acidic pH conditions (pH 2-3) compared to Acidobacteria from soils,[19] potentially due to cell specialization and enzyme stability.[7]

The G+C content of Acidobacteria genomes are consistent within their subdivisions - above 60% for group V fragments and roughly 10% lower for group III fragments.[3]

The majority of Acidobacteria are considered aerobes.[20][21] There are some Acidobacteria that are considered anaerobes within subdivision 8[22] and subdivision 23.[23] It has been found that some strains of Acidobacteria originating from soils have the genomic potential to respire oxygen at atmospheric and sub-atmospheric concentrations.[21]

Members of the Acidobacteria phylum have been considered oligotrophic bacteria due to high abundances in low organic carbon environments.[7] However, the variation in this phylum may indicate that they may not have the same ecological strategy.[7]

The first species, Acidobacterium capsulatum, of this phylum was discovered in 1991.[24] However, Acidobacteria were not recognized as a novel division until 1997,[10] and were not recognized as a phylum until 2012.[25]

There has been no clear evidence that Acidobacteria are involved in nitrogen-cycle processes such as nitrification, denitrification, or nitrogen fixation.[7] However, Geothrix fermantans was shown to be able to reduce nitrate and contained the norB gene.[7] The NorB gene was also identified in Koribacter verstailis and Solibacter usitatus.[29][7] In addition, the presence of the nirA gene has been observed in members of subdivision 1.[7] Additionally, to date, all genomes have been described to directly uptake ammonium via ammonium channel transporter family genes.[21][7] Acidobacteria can use both inorganic and organic nitrogen as their nitrogen sources.